 
 (declare new-document-ui)
 
-(defrecord NewDocumentColumnSource [id]
+(defrecord NewDocumentColumn [id]
   SpecialColumn
   (special-column-ui [_] new-document-ui)
-  ColumnSource
-  (column-title [_ _]
-    "Create New Document")
-  (column-header-url [_] nil)
-  (column-pages [_ _] [])
-  (remove-pages! [_ state page-ids]
-    (assert false "Can't remove pages from NewDocumentColumnSource"))
   ColumnDropTarget
   (accept-drop! [_ state new-pages _]
     (go

      (let [gen (IdGenerator.getInstance)
            columns (for [column columns]
                      (match [column]
                        [[:document id]] (->DocumentColumnSource (.getNextUniqueId gen) id)
                        [[:inbox _]]     (->InboxColumnSource (.getNextUniqueId gen))
                        [[:new-document _]]     (->NewDocumentColumnSource (.getNextUniqueId gen))))]
        (filterv identity columns)))))

(defn- prepare-columns! [props state owner]

                                          source-column
                                          page-ids
                                          0)))}
     [:header nil]
     [:.center
      "Drag pages here or press \"Open to open a file or document"
      [:button {:on-click (fn [e]
